This invention relates generally to shut off valves and more particularly to an acceleration sensitive shut off valve for firefighting equipment such as portable monitors.
Firefighting monitors are used to deliver large quantities of water or foam in firefighting situations. A monitor has an inlet connected to a hose or pipe and a discharge on which a nozzle is mounted. The monitor itself typically is made from two or more rigid sections that can be adjusted relative to one another to redirect a stream of fluid in vertical and horizontal directions. The objective of a monitor is to serve as a support for a nozzle so the nozzle can deliver large volumes of fluid in firefighting situations. A consequence of large flow firefighting nozzles is that they generate large reaction forces that can not be restrained by hand. Reaction forces vary depending upon flow volume and pressure. The reaction force is always opposite the direction at which the stream is directed. As a result, any device or monitor configuration that is used to resist the reaction forces must take into account a number of variables.
Portable monitors are moved around to attack fires from various locations and angles. A portable monitor may be set on a variety of surfaces. Leg spikes and tie down straps can be used to secure the monitor against movement. Some surfaces are better able to resist the reaction forces than others. On smooth surfaces a monitor may tend to slide forward as its hose is being charged with water and then slide back or to the side when the stream exits the nozzle while fighting a fire. As the elevation angle is lowered the tendency for the portable monitor to slide is increased due to the horizontal component of the nozzle reaction forces being increased. Typically, a firefighter can prevent movement of the monitor by tying it down or operating it at high elevation angles, but on occasion, a monitor may slip out of control with the possibility of human injury or property damage. At the least, the monitor stream will be redirected away from the point intended by the firefighter.
The tendency to resist sliding can be increased by adding weight to the monitor, but added weight inhibits ease of repositioning a monitor. Sliding can also be resisted by looping hose around the monitor to add weight. Multiple hoses can be used to feed a monitor and provide added stability, but more expensive multiple inlets are required. Multiple hoses require more set up time than a single hose and repositioning a monitor with multiple hoses is more difficult. Multiple hose lines consume more space and have limited usefulness inside of burning structures.
The ability to control the flow of water may be desirable to control the nozzle reaction forces to safe levels, limit water or foam usage, or reduce water damage. Current portable monitors do not have a manual shut off valve. To stop or limit fluid flow through these monitors, the fluid must be shut off at a remote location such as the fire truck, fire hydrant, or a valve in a hose line. Typically, there is considerable distance between the monitor and the shut off valve and noise at the fire scene makes communication between the operating crew very difficult, necessitating radio communication. A separate valve added to the inlet or discharge of a monitor is possible, but would add substantial weight and size to the unit. More size and weight in turn makes repositioning the monitor more difficult. Some specialty nozzles have shut off valves built in, but these are limited in size and type and, thus, can not be relied upon for all circumstances.
Further, not all valve types are practical for use in a portable monitor because turbulence through a valve can make the portable monitor more difficult to manage and limit the nozzle""s reach. Slide type valves such as those disclosed in U.S. Pat. Nos. 4,252,278; 4,470,549; and 4,589,439 introduce minimal turbulence. Despite the benefits of this type of valve, no portable monitor has ever used a slide type valve.
It is sometimes desired to add a hose or dividing valve to the discharge of a portable monitor to extend firefighting operations. Therefore, monitors must first be shut off and then the nozzle must be removed to add hose or dividing valves.
One monitor available from Task Force Tips, Inc. of Valparaiso, Ind. under the trademark Crossfire(copyright) and described in U.S. Pat. No. 5,593,092, has an automatic valve built into it. The valve can not be used to regulate the flow of the water, nor can it completely shut off the flow of water. Once set to an open position, the valve can not be manually closed. This valve automatically reduces flow if the monitor moves, particularly if that movement is to tip over the monitor. This device is useful and has added considerably to the safe use of portable monitors. Nonetheless, the Crossfire(copyright) has a trip mechanism that must be in contact with the ground while the monitor is in use. Uneven or soft ground can result in inadvertent closure of the valve. While this monitor is safer than others commercially available, sliding movement where the trip mechanism is still in contact with the ground can still cause injury or property damage or simply a disruption in firefighting operations. Consequently, even such a safe monitor should be tied down when in use, thereby limiting somewhat, the ability to quickly reposition the monitor.
Thus, there is a need for an improved monitor valve that can be controlled at the monitor without the cooperation of an operator at a remote location. Further, there is a need for a shut off valve that requires no interaction with the ground and is also sensitive to acceleration in addition to tipping movement.
The present invention provides a monitor with a valve that can be controlled by a monitor operator. The valve may include an acceleration sensitive shut off device that reacts when the monitor accelerates or tips. The valve is triggered by a device that requires no contact with the ground or other external surface.
Another object of the present invention is to provide a portable monitor that is easily repositioned even inside burning structures and on surfaces of different elevations.
Another object of the present invention is to enable the safe use of extremely low discharge angles by having a valve that shuts off should the monitor accelerate.
Another object of the present invention is to provide a portable monitor that can have fluid flow controlled at the monitor for quicker changing of nozzle, hoses, and dividing valves.
Another object of this invention is to include an acceleration sensitive shut off valve that moves the valve toward a closed position at a speed that limits the danger of the monitor whipping out of control.
Another object of the present invention is to integrate a shut off valve into a monitor without substantially increasing monitor weight and size.
It is yet another object of the present invention to provide a monitor valve that can be operated in a variety of valve flow positions with minimum turbulence to maximize stream reach.
Thus, to meet these and other objectives, there is provided by the present invention a valve having an open position and a closed position, the valve being biased toward the closed position and including: a housing defining a recess; a handle operatively mounted to the housing for moving the valve to the open position; a sear for engaging the handle when the valve is in the open position; a sear spring for urging the sear into engagement with the handle when the valve is in the open position; a release for disengaging the sear from the handle; and a bearing member disposed in the recess of the housing and in bearing support of the release when the valve is in the open position, whereby dislodging the bearing member from the recess removes the bearing member from bearing support of the release, moves the release to disengage the sear from the handle, to move the valve toward the closed position.
The valve can be a slide type valve or any other valve suitable for use with the high flows experienced by monitors.
The valve housing recess may be a groove and the bearing member can be one or more rods that rest in the groove. The bearing member can be two or more rods disposed end-to-end in the groove when the valve is in the open position.
The valve can have a plurality of open positions and the handle can be adapted to move the valve between the closed position and any of the open positions.
The sear spring can be a leaf spring, and it can have a first end fixed to the sear and a second end for engagement by the release. The release can be pivotably mounted to the housing. Preferably, the bearing member returns to the recess by gravity when the valve is in the closed position.
The valve housing can, and preferably does, include a firefighting monitor.
The valve can include a dampener to slow the closing of the valve after the sear releases the handle. The dampener can include a chamber fixed to the housing; a pivot fixed to the valve handle for movement with the valve and valve handle between the open position and the closed position, the pivot disposed in the chamber; and a fluid disposed in the chamber and substantially surrounding the pivot, the fluid having a viscosity greater than the viscosity of air.
The valve release can be pivotably mounted to the housing and have a first end on one side of the pivot and a second end on the opposite side of the pivot; the first end for engaging the sear spring; and the second end including a bearing surface for bearing on the bearing member when the valve is in the open position.
A monitor in accordance with the present invention includes: a housing defining a water passage; a valve disposed in the water passage, for moving between an open position and a closed position and being biased toward the closed position; a valve handle for moving the valve between the open position and the closed position; a sear for engaging the valve handle in the open position; a sear spring for urging the sear into engagement with the handle in the open position; a release mounted on the housing and having a release portion for moving the sear out of engagement with the handle; and; an acceleration sensor joined to the housing and disposed to engage the release to move the sear out of engagement with the handle and thereby close the valve when the housing experiences acceleration.
A portable monitor in accordance with the present invention includes: a housing defining a water passage; a valve disposed in the water passage movable between an open position and a closed position; a valve handle for moving the valve between the open position and the closed position; and an acceleration sensitive device joined to the housing and operable to close the valve when the housing experiences acceleration.